The one thing I wanted to do was to find large packages installed on the system. I then read about dpigs, which is part of the debian-goodies package (see http://manpages.ubuntu.com/manpages/hardy/en/man1/dpigs.1.html). This is a great tool that lists the top 10 largest packages. I was able to clean several hundred megabytes from the system by looking at the packages and removing them.

Using dpigs, I brought the custom installation CD size down to 519 MB from over 700 MB without losing any additional functionality.